Keeping zones open with intermediate padding

ABSTRACT

The present disclosure generally relates to methods of operating storage devices. The storage device comprises a controller and a media unit divided into a plurality of zones. Data associated with one or more first commands is written to a first portion of a first zone. Upon a predetermined amount of time passing, dummy data is written to a second portion of the first zone to fill the first zone to a zone capacity. Upon receiving one or more second commands to write data, a second zone is allocated and opened, and the data associated with the one or more second commands is written to a first portion of the second zone. The data associated with the one or more first commands is then optionally re-written to a second portion of the second zone to fill the second zone to a zone capacity, and the first zone is erased.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 16/853,408, filed Apr. 20, 2020, which is herein incorporatedby reference.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

Embodiments of the present disclosure generally relate to storagedevices, such as sold state drives (SSDs).

Description of the Related Art

Storage devices, such as SSDs, may be used in computers in applicationswhere relatively low latency and high capacity storage are desired. Forexample, SSDs may exhibit lower latency, particularly for random readsand writes, than hard disk drives (HDDs). Typically, a controller of theSSD receives a command to read or write data from a host device to amemory device. The data is read and written to one or more erase blocksin the memory device. Each logical block address is associated with aphysical location on an erase block so that the SSD and/or the hostdevice know the location of where the data is stored. One or more eraseblocks may be grouped together by their respective logical blockaddresses to form a grouping or a zone. Data is typically written toeach of the erase blocks in a grouping or a zone prior to writing datato erase blocks in a new grouping or a new zone.

As data is written to erase blocks of a grouping or zone, the groupingor zone may be partially full for an amount of time. The longer theamount of time the grouping or zone remains partially full, the moreprone to errors the grouping or zone becomes. As such, the data storedin the partially full grouping or zone may become lost or damaged,negatively affecting the reliability of the data.

Therefore, what is needed is a new method of operating a storage devicethat decreases the error rate of data stored in the storage device andimproves the reliability of the data.

SUMMARY OF THE DISCLOSURE

The present disclosure generally relates to methods of operating storagedevices. The storage device comprises a controller and a media unitdivided into a plurality of zones. Data associated with one or morefirst commands is written to a first portion of a first zone. Upon apredetermined amount of time passing, dummy data is written to a secondportion of the first zone to fill the first zone to a zone capacity.Upon receiving one or more second commands to write data, a second zoneis allocated and opened, and the data associated with the one or moresecond commands is written to a first portion of the second zone. Thedata associated with the one or more first commands is then optionallyre-written to a second portion of the second zone to fill the secondzone to a zone capacity, and the first zone is erased.

In one embodiment, a storage device comprises of a media unit, whereinthe capacity of the media unit is divided into a plurality of zones. Themedia unit comprises a plurality of dies and each of the plurality ofdies comprises a plurality of erase blocks. The storage device furthercomprises a controller coupled to the media unit. The controller isconfigured to receive one or more first commands to write data to afirst zone of the plurality of zones, wherein the data associated withthe one or more first commands is written to a first portion of thefirst zone, and wherein a second portion of the first zone remainsavailable to write data to. The controller is also configured todetermine a predetermined amount of time has passed since receiving afirst command to write data to the first zone and write dummy data tothe second portion of the first zone to fill the first zone to a zonecapacity. The controller is further configured to open a second zone andwrite the data associated with the one or more second commands to afirst portion of the second zone upon receiving one or more secondcommands to write data to the first zone. The controller is alsoconfigured to re-write the data associated with the one or more firstcommands written to the first portion of the first zone to a secondportion of the second zone.

In another embodiment, a storage device comprises of a media unit,wherein a capacity of the media unit is divided into a plurality ofzones. The media unit comprises a plurality of dies and each of theplurality of dies comprises a plurality of erase blocks. The storagedevice further comprises a controller coupled to the media unit. Thecontroller is configured to receive one or more first commands to writedata to a first zone of the plurality of zones, wherein the dataassociated with the one or more first commands is written to a firstportion of the first zone, and wherein a second portion of the firstzone remains available to write data to. The controller is alsoconfigured to determine a first predetermined amount of time has passedsince receiving a first command to write data to the first zone. Thecontroller is further configured to open a second zone and write thedata associated with the one or more second commands to a first portionof the second zone upon receiving one or more second commands to writedata to the first zone. The controller is also configured to determine asecond predetermined amount of time has passed since receiving a secondcommand to write data to the first zone. The controller is furtherconfigured to open a third zone and write the data associated with theone or more third commands to a first portion of the third zone uponreceiving one or more third commands to write data to the first zone.The controller is also configured to re-write the data associated withthe one or more first commands written to the first portion of the firstzone to a second portion of the third zone, and re-write the dataassociated with the one or more second commands written to the firstportion of the second zone to a third portion of the third zone.

In another embodiment, a storage device comprises of a media unit,wherein a capacity of the media unit is divided into a plurality ofzones. The media unit comprises a plurality of dies and each of theplurality of dies comprises a plurality of erase blocks. The storagedevice further comprises a controller coupled to the media unit. Thecontroller is configured to write data associated with one or more firstcommands to a first portion of a first zone, and wherein a secondportion of the first zone remains available to write data to. Thecontroller is also configured to write dummy data to the second portionof the first zone to fill the first zone to a zone capacity. Thecontroller is further configured to open a second zone and write thedata associated with the one or more second commands to a first portionof the second zone upon receiving one or more second commands to writedata to the first zone. The controller is also configured to re-writethe data associated with the one or more first commands written to thefirst portion of the first zone to a second portion of the second zone.The controller is further configured to write dummy data to a thirdportion of the second zone to fill the second zone to a zone capacityupon the timer expiring a second time. The controller is also configuredto open a third zone and write the data associated with the one or morethird commands to a first portion of the third zone upon receiving oneor more third commands to write data to the first zone. The controlleris further configured to re-write the data associated with the one ormore first commands written to the second portion of the second zone toa second portion of the third zone, and re-write the data associatedwith the one or more second commands written to the first portion of thesecond zone to a third portion of the third zone.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 is a schematic block diagram illustrating a storage system,according to one embodiment.

FIG. 2 illustrates a storage system comprising a storage device coupledto a host device, according to another embodiment.

FIG. 3 is a block diagram illustrating a method of operating a storagedevice to execute a read or write command, according to one embodiment.

FIG. 4A illustrates a Zoned Namespaces view utilized in a storagedevice, according to one embodiment.

FIG. 4B illustrates a state diagram for the Zoned Namespaces of thestorage device of FIG. 4A, according to one embodiment.

FIG. 5A is a schematic illustration of a ZNS of a storage device storingdata, according to one embodiment.

FIG. 5B is a flowchart illustrating a method of writing data to the ZNSof FIG. 5A, according to one embodiment.

FIG. 6A is a schematic illustration of a ZNS of a storage device storingdata, according to another embodiment.

FIG. 6B is a flowchart illustrating a method of writing data to the ZNSof FIG. 6A, according to one embodiment.

FIG. 7A is a schematic illustration of a ZNS of a storage device storingdata, according to yet another embodiment.

FIG. 7B is a flowchart illustrating a method of writing data to the ZNSof FIG. 7A, according to one embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

In the following, reference is made to embodiments of the disclosure.However, it should be understood that the disclosure is not limited tospecific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practice thedisclosure. Furthermore, although embodiments of the disclosure mayachieve advantages over other possible solutions and/or over the priorart, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the disclosure. Thus, the followingaspects, features, embodiments and advantages are merely illustrativeand are not considered elements or limitations of the appended claimsexcept where explicitly recited in a claim(s). Likewise, reference to“the disclosure” shall not be construed as a generalization of anyinventive subject matter disclosed herein and shall not be considered tobe an element or limitation of the appended claims except whereexplicitly recited in a claim(s).

The present disclosure generally relates to methods of operating storagedevices. The storage device comprises a controller and a media unitdivided into a plurality of zones. Data associated with one or morefirst commands is written to a first portion of a first zone. Upon apredetermined amount of time passing, dummy data is written to a secondportion of the first zone to fill the first zone to a zone capacity.Upon receiving one or more second commands to write data, a second zoneis allocated and opened, and the data associated with the one or moresecond commands is written to a first portion of the second zone. Thedata associated with the one or more first commands is then optionallyre-written to a second portion of the second zone to fill the secondzone to a zone capacity, and the first zone is erased.

FIG. 1 is a schematic block diagram illustrating a storage system 100 inwhich storage device 106 may function as a storage device for a hostdevice 104, in accordance with one or more techniques of thisdisclosure. For instance, the host device 104 may utilize non-volatilememory devices 110 included in storage device 106 to store and retrievedata. The host device 104 comprises a host DRAM 138. In some examples,the storage system 100 may include a plurality of storage devices, suchas the storage device 106, which may operate as a storage array. Forinstance, the storage system 100 may include a plurality of storagedevices 106 configured as a redundant array of inexpensive/independentdisks (RAID) that collectively function as a mass storage device for thehost device 104.

The storage system 100 includes a host device 104 which may store and/orretrieve data to and/or from one or more storage devices, such as thestorage device 106. As illustrated in FIG. 1 , the host device 104 maycommunicate with the storage device 106 via an interface 114. The hostdevice 104 may comprise any of a wide range of devices, includingcomputer servers, network attached storage (NAS) units, desktopcomputers, notebook (i.e., laptop) computers, tablet computers, set-topboxes, telephone handsets such as so-called “smart” phones, so-called“smart” pads, televisions, cameras, display devices, digital mediaplayers, video gaming consoles, video streaming device, and the like.

The storage device 106 includes a controller 108, non-volatile memory110 (NVM 110), a power supply 111, volatile memory 112, and an interface114. The controller 108 comprises an internal memory 120 or buffer. Insome examples, the storage device 106 may include additional componentsnot shown in FIG. 1 for sake of clarity. For example, the storage device106 may include a printed circuit board (PCB) to which components of thestorage device 106 are mechanically attached and which includeselectrically conductive traces that electrically interconnect componentsof the storage device 106, or the like. In some examples, the physicaldimensions and connector configurations of the storage device 106 mayconform to one or more standard form factors. Some example standard formfactors include, but are not limited to, 3.5″ data storage device (e.g.,an HDD or SSD), 2.5″ data storage device, 1.8″ data storage device,peripheral component interconnect (PCI), PCI-extended (PCI-X), PCIExpress (PCIe) (e.g., PCIe×1, ×4, ×8, ×16, PCIe Mini Card, MiniPCI,etc.). In some examples, the storage device 106 may be directly coupled(e.g., directly soldered) to a motherboard of the host device 104.

The interface 114 of the storage device 106 may include one or both of adata bus for exchanging data with the host device 104 and a control busfor exchanging commands with the host device 104. The interface 114 mayoperate in accordance with any suitable protocol. For example, theinterface 114 may operate in accordance with one or more of thefollowing protocols: advanced technology attachment (ATA) (e.g.,serial-ATA (SATA) and parallel-ATA (PATA)), Fibre Channel Protocol(FCP), small computer system interface (SCSI), serially attached SCSI(SAS), PCI, PCIe, non-volatile memory express (NVMe), OpenCAPI, GenZ,Cache Coherent Interface Accelerator (CCIX), Compute Express Link (CXL),Open Channel SSD (OCSSD), or the like. The electrical connection of theinterface 114 (e.g., the data bus, the control bus, or both) iselectrically connected to the controller 108, providing electricalconnection between the host device 104 and the controller 108, allowingdata to be exchanged between the host device 104 and the controller 108.In some examples, the electrical connection of the interface 114 mayalso permit the storage device 106 to receive power from the host device104. For example, as illustrated in FIG. 1 , the power supply 111 mayreceive power from the host device 104 via the interface 114.

The storage device 106 includes NVM 110, which may include a pluralityof memory devices or media units. NVM 110 may be configured to storeand/or retrieve data. For instance, a media unit of NVM 110 may receivedata and a message from the controller 108 that instructs the media unitto store the data. Similarly, the media unit of NVM 110 may receive amessage from the controller 108 that instructs the media unit toretrieve data. In some examples, each of the media units may be referredto as a die. In some examples, a single physical chip may include aplurality of dies (i.e., a plurality of media units). In some examples,each media unit may be configured to store relatively large amounts ofdata (e.g., 128 MB, 256 MB, 512 MB, 1 GB, 2 GB, 4 GB, 8 GB, 16 GB, 32GB, 64 GB, 128 GB, 256 GB, 512 GB, 1 TB, etc.).

In some examples, each media unit of NVM 110 may include any type ofnon-volatile memory devices, such as flash memory devices, phase-changememory (PCM) devices, resistive random-access memory (ReRAM) devices,magnetoresistive random-access memory (MRAM) devices, ferroelectricrandom-access memory (F-RAM), holographic memory devices, and any othertype of non-volatile memory devices.

The NVM 110 may comprise a plurality of flash memory devices or mediaunits. Flash memory devices may include NAND or NOR based flash memorydevices, and may store data based on a charge contained in a floatinggate of a transistor for each flash memory cell. In NAND flash memorydevices, the flash memory device may be divided into a plurality ofblocks which may divided into a plurality of pages. Each block of theplurality of blocks within a particular memory device may include aplurality of NAND cells. Rows of NAND cells may be electricallyconnected using a word line to define a page of a plurality of pages.Respective cells in each of the plurality of pages may be electricallyconnected to respective bit lines. Furthermore, NAND flash memorydevices may be 2D or 3D devices, and may be single level cell (SLC),multi-level cell (MLC), triple level cell (TLC), or quad level cell(QLC). The controller 108 may write data to and read data from NANDflash memory devices at the page level and erase data from NAND flashmemory devices at the block level.

The storage device 106 includes a power supply 111, which may providepower to one or more components of the storage device 106. Whenoperating in a standard mode, the power supply 111 may provide power tothe one or more components using power provided by an external device,such as the host device 104. For instance, the power supply 111 mayprovide power to the one or more components using power received fromthe host device 104 via the interface 114. In some examples, the powersupply 111 may include one or more power storage components configuredto provide power to the one or more components when operating in ashutdown mode, such as where power ceases to be received from theexternal device. In this way, the power supply 111 may function as anonboard backup power source. Some examples of the one or more powerstorage components include, but are not limited to, capacitors, supercapacitors, batteries, and the like. In some examples, the amount ofpower that may be stored by the one or more power storage components maybe a function of the cost and/or the size (e.g., area/volume) of the oneor more power storage components. In other words, as the amount of powerstored by the one or more power storage components increases, the costand/or the size of the one or more power storage components alsoincreases.

The storage device 106 also includes volatile memory 112, which may beused by controller 108 to store information. Volatile memory 112 may becomprised of one or more volatile memory devices. In some examples, thecontroller 108 may use volatile memory 112 as a cache. For instance, thecontroller 108 may store cached information in volatile memory 112 untilcached information is written to non-volatile memory 110. As illustratedin FIG. 1 , volatile memory 112 may consume power received from thepower supply 111. Examples of volatile memory 112 include, but are notlimited to, random-access memory (RAM), dynamic random access memory(DRAM), static RAM (SRAM), and synchronous dynamic RAM (SDRAM (e.g.,DDR1, DDR2, DDR3, DDR3L, LPDDR3, DDR4, LPDDR4, DDR5, LPDDR5, and thelike)).

The storage device 106 includes a controller 108, which may manage oneor more operations of the storage device 106. For instance, thecontroller 108 may manage the reading of data from and/or the writing ofdata to the NVM 110. In some embodiments, when the storage device 106receives a write command from the host device 104, the controller 108may initiate a data storage command to store data to the NVM 110 andmonitor the progress of the data storage command. The controller 108 maydetermine at least one operational characteristic of the storage system100 and store the at least one operational characteristic to the NVM110. In some embodiments, when the storage device 106 receives a writecommand from the host device 104, the controller 108 temporarily storesthe data associated with the write command in the internal memory 120before sending the data to the NVM 110.

FIG. 2 illustrates a storage system 200 comprising a storage device 206coupled to a host device 204, according to another embodiment. Storagesystem 200 may be the storage system 100, the host device 104, and thestorage device 106 of FIG. 1 .

The storage device 206 may send and receive commands and data from thehost device 204, and comprises a command processor 220. The commandprocessor 220 may be the controller 108 of FIG. 1 . The commandprocessor 220 may schedule memory device access, such as NAND access,and may perform a read to a memory device prior to a previously receivedcommand requiring a write to the same memory device. The commandprocessor 220 is coupled to one or more memory devices 228 and a commandfetch 222. The one or more memory devices 228 may be NAND non-volatilememory devices. The command fetch 222 is coupled to a submission queuearbitration 224. The submission queue arbitration 224 is coupled to oneor more submission queue head and tail pointers 226.

The host device 204 is comprised of one or more host softwareapplications 232 coupled to one or more processing units or CPUapplications 234. In one embodiment, the software application 232 haslimited solid-state drive queue depth in order to derive a latency QoSfor each user of the system 200. The host device 204 further comprisesan operating system (OS) or software application 240 without anassociated QoS. The CPU 234 is coupled to an interconnect 236 and to ahost DRAM 238. The host DRAM 238 may store submission queue data. Theinterconnect 236 is coupled to the storage device 206. The interconnect236 may be in communication with both the submission queue head and tailpointers 226 and the command fetch 222.

The CPU 234 generates one or more commands 216 to send to the storagedevice 206, and may send and receive commands from the storage device206 via the command fetch signal 244. The CPU 234 may further send aninterrupt or doorbell 218 to the storage device 206 to notify thestorage device 206 of the one or more commands 216. The CPU 234 maylimit data-queue depth submitted to the storage device 206. Queue depth(QD) is the maximum number of commands queued to the storage device 206,and data-QD is the amount of data associated with the commands queuedwith a QD. In one embodiment, the data-QD 242 of the storage device 206is equal to the bandwidth of the storage device 206. Data-QD 242 islimited to the highest level under which the storage device 206 canstill maintain a desired latency QoS. The command processor 220 thenprocesses the commands received from the host device 204.

FIG. 3 is a block diagram illustrating a method 300 of operating astorage device to execute a read or write command, according to oneembodiment. Method 300 may be used with the storage system 100 having ahost device 104 and a storage device 106 comprising a controller 108.Method 300 may further be used with the storage system 200 having a hostdevice 204 and a storage device 206 comprising a command processor 220.

Method 300 begins at operation 350, where the host device writes acommand into a submission queue as an entry. The host device may writeone or more commands into the submission queue at operation 350. Thecommands may be read commands or write commands. The host device maycomprise one or more submission queues.

In operation 352, the host device writes one or more updated submissionqueue tail pointers and rings a doorbell or sends an interrupt signal tonotify or signal the storage device of the new command that is ready tobe executed. The doorbell signal may be the doorbell 218 of FIG. 2 . Thehost may write an updated submission queue tail pointer and send adoorbell or interrupt signal for each of the submission queues if thereare more than one submission queues. In operation 354, in response toreceiving the doorbell or interrupt signal, a controller of the storagedevice fetches the command from the one or more submission queue, andthe controller receives the command.

In operation 356, the controller processes the command and writes ortransfers data associated with the command to the host device memory.The controller may process more than one command at a time. Thecontroller may process one or more commands in the submission order orin the sequential order. Processing a write command may compriseidentifying a zone to write the data associated with the command to,writing the data to one or more logical block addresses (LBA) of thezone, and advancing a write pointer of the zone to identify the nextavailable LBA within the zone.

In operation 358, once the command has been fully processed, thecontroller writes a completion entry corresponding to the executedcommand to a completion queue of the host device and moves or updatesthe CQ head pointer to point to the newly written completion entry.

In operation 360, the controller generates and sends an interrupt signalor doorbell to the host device. The interrupt signal indicates that thecommand has been executed and data associated with the command isavailable in the memory device. The interrupt signal further notifiesthe host device that the completion queue is ready to be read orprocessed.

In operation 362, the host device processes the completion entry. Inoperation 364, the host device writes an updated CQ head pointer to thestorage device and rings the doorbell or sends an interrupt signal tothe storage device to release the completion entry.

FIG. 4A illustrates a Zoned Namespaces (ZNS) 402 view utilized in astorage device 400, according to one embodiment. The storage device 400may present the ZNS 402 view to a host device. FIG. 4B illustrates astate diagram 450 for the ZNS 402 of the storage device 400, accordingto one embodiment. The storage device 400 may be the storage device 106of the storage system 100 of FIG. 1 or the storage device 206 of thestorage system 200 of FIG. 2 . The storage device 400 may have one ormore ZNS 402, and each ZNS 402 may be different sizes. The storagedevice 400 may further comprise one or more conventional namespaces inaddition to the one or more Zoned Namespaces 402. Moreover, the ZNS 402may be a zoned block command (ZBC) for SAS and/or a zoned-device ATAcommand set (ZAC) for SATA. Host side zone activity may be more directlyrelated to media activity in zoned drives due to the relationship oflogical to physical activity possible.

In the storage device 400, the ZNS 402 is the quantity of NVM that canbe formatted into logical blocks such that the capacity is divided intoa plurality of zones 406 a-406 n (collectively referred to as zones406). Each of the zones 406 comprise a plurality of physical or eraseblocks (now shown) of a media unit or NVM 404, and each of the eraseblocks are associated a plurality of logical blocks (not shown). Whenthe controller 408 receives a command, such as from a host device (notshown) or the submission queue of a host device, the controller 408 canread data from and write data to the plurality of logical blocksassociated with the plurality of erase blocks (EBs) of the ZNS 402. Eachof the logical blocks is associated with a unique LBA or sector.

In one embodiment, the NVM 404 is a NAND device. The NAND devicecomprises one or more dies. Each of the one or more dies comprises oneor more planes. Each of the one or more planes comprises one or moreerase blocks. Each of the one or more erase blocks comprises one or morewordlines (e.g., 256 wordlines). Each of the one or more wordlines maybe addressed in one or more pages. For example, an MLC NAND die may useupper page and lower page to reach the two bits in each cell of the fullwordline (e.g., 16 kB per page). Furthermore, each page can be accessedat a granularity equal to or smaller than the full page. A controllercan frequently access NAND in user data granularity LBA sizes of 512bytes. Thus, as referred to throughout, NAND locations are equal to agranularity of 512 bytes. As such, an LBA size of 512 bytes and a pagesize of 16 KiB for two pages of an MLC NAND results in 32 LBAs perwordline. However, the NAND location size is not intended to belimiting, and is merely used as a non-limiting example.

When data is written to an erase block, one or more logical blocks arecorrespondingly updated within a zone 406 to track where the data islocated within the NVM 404. Data may be written to one zone 406 at atime until a zone 406 is full, or to multiple zones 406 such thatmultiple zones 406 may be partially full. Similarly, when writing datato a particular zone 406, data may be written to the plurality of eraseblocks one block at a time, in sequential order of NAND locations,page-by-page, or wordline-by-wordline, until moving to an adjacent block(i.e., write to a first erase block until the first erase block is fullbefore moving to the second erase block), or to multiple blocks at once,in sequential order of NAND locations, page-by-page, orwordline-by-wordline, to partially fill each block in a parallel fashion(i.e., writing the first NAND location or page of each erase blockbefore writing to the second NAND location or page of each erase block).This sequential programming of every NAND location is a typicalnon-limiting requirement of many NAND EBs.

Each of the zones 406 is associated with a zone starting logical blockaddress (ZSLBA). The ZSLBA is the first available LBA in the zone 406.For example, the first zone 406 a is associated with Z_(a)SLBA, thesecond zone 406 b is associated with Z_(b)SLBA, the third zone 406 c isassociated with Z_(c)SLBA, the fourth zone 406 d is associated withZ_(d)SLBA, and the n^(th) zone 406 n (i.e., the last zone) is associatedwith Z_(n)SLBA. Each zone 406 is identified by its ZSLBA, and isconfigured to receive sequential writes (i.e., writing data to the NVM110 in the order the write commands are received).

As data is written to a zone 406, a write pointer 410 is advanced orupdated to point to or to indicate the next available block in the zone406 to write data to in order to track the next write starting point(i.e., the completion point of the prior write equals the starting pointof a subsequent write). Thus, the write pointer 410 indicates where thesubsequent write to the zone 406 will begin. Subsequent write commandsare ‘zone append’ commands, where the data associated with thesubsequent write command appends to the zone 406 at the location thewrite pointer 410 is indicating as the next starting point. An orderedlist of LBAs within the zone 406 may be stored for write ordering. Eachzone 406 may have its own write pointer 410. Thus, when a write commandis received, a zone 406 is identified by its ZSLBA, and the writepointer 410 determines where the write of the data begins within theidentified zone 406.

FIG. 4B illustrates a state diagram 450 for the ZNS 402 of FIG. 4A. Inthe state diagram 450, each zone may be in a different state, such asempty, active, full, or offline. When a zone is empty, the zone is freeof data (i.e., none of the erase blocks in the zone are currentlystoring data) and the write pointer is at the ZSLBA (i.e., WP=0). Anempty zone switches to an open and active zone once a write is scheduledto the zone or if a zone open command is issued by the host. Zonemanagement (ZM) commands can be used to move a zone between zone openand zone closed states, which are both active states. If a zone isactive, the zone comprises open blocks that may be written to, and thehost may be provided a description of recommended time in the activestate by the ZM or the controller. The controller may comprise the ZM.

The term “written to” includes programming user data on 0 or more wordlines in an erase block, erasure, and/or partially filled word lines inan erase block when user data has not filled all of the available wordlines. The term “written to” may further include closing a zone due tointernal drive handling needs (open block data retention concernsbecause the bits in error accumulate more quickly on open erase blocks),the storage device 400 closing a zone due to resource constraints, liketoo many open zones to track or discovered defect state, among others,or a host device closing the zone for concerns such as there being nomore data to send the drive, computer shutdown, error handling on thehost, limited host resources for tracking, among others.

The active zones may be either open or closed. An open zone is an emptyor partially full zone that is ready to be written to and has resourcescurrently allocated. The data received from the host device with a writecommand or zone append command may be programmed to an open erase blockthat is not currently filled with prior data. New data pulled-in fromthe host device or valid data being relocated may be written to an openzone. Valid data may be moved from one zone (e.g. the first zone 402 a)to another zone (e.g. the third zone 402 c) for garbage collectionpurposes. A closed zone is an empty or partially full zone that is notcurrently receiving writes from the host in an ongoing basis. Themovement of a zone from an open state to a closed state allows thecontroller 408 to reallocate resources to other tasks. These tasks mayinclude, but are not limited to, other zones that are open, otherconventional non-zone regions, or other controller needs.

In both the open and closed zones, the write pointer is pointing to aplace in the zone somewhere between the ZSLBA and the end of the lastLBA of the zone (i.e., WP>0). Active zones may switch between the openand closed states per designation by the ZM, or if a write is scheduledto the zone. Additionally, the ZM may reset an active zone to clear orerase the data stored in the zone such that the zone switches back to anempty zone. Once an active zone is full, the zone switches to the fullstate. A full zone is one that is completely filled with data, and hasno more available sectors or LBAs to write data to (i.e., WP=zonecapacity (ZCAP)). Read commands of data stored in full zones may stillbe executed.

The ZM may reset a full zone, scheduling an erasure of the data storedin the zone such that the zone switches back to an empty zone. When afull zone is reset, the zone may not be immediately cleared of data,though the zone may be marked as an empty zone ready to be written to.However, the reset zone must be erased prior to switching to an activezone. A zone may be erased any time between a ZM reset and a ZM open. Anoffline zone is a zone that is unavailable to write data to. An offlinezone may be in the full state, the empty state, or in a partially fullstate without being active.

Since resetting a zone clears or schedules an erasure of the data storedin the zone, the need for garbage collection of individual erase blocksis eliminated, improving the overall garbage collection process of thestorage device 400. The storage device 400 may mark one or more eraseblocks for erasure. When a new zone is going to be formed and thestorage device 400 anticipates a ZM open, the one or more erase blocksmarked for erasure may then be erased. The storage device 400 mayfurther decide and create the physical backing of the zone upon erase ofthe erase blocks. Thus, once the new zone is opened and erase blocks arebeing selected to form the zone, the erase blocks will have been erased.Moreover, each time a zone is reset, a new order for the LBAs and thewrite pointer 410 for the zone 406 may be selected, enabling the zone406 to be tolerant to receive commands out of sequential order. Thewrite pointer 410 may optionally be turned off such that a command maybe written to whatever starting LBA is indicated for the command.

Referring back to FIG. 4A, when the host sends a write command to writedata to a zone 406, the controller 408 pulls-in the write command andidentifies the write command as a write to a newly opened zone 406. Thecontroller 408 selects a set of EBs to store the data associated withthe write commands of the newly opened zone 406 to, and the newly openedzone 406 switches to an active zone 406. As used herein, the controller408 initiating, receiving, or pulling-in a write command comprisesreceiving a write command or direct memory access (DMA) reading thewrite command. The write command may be a command to write new data, ora command to move valid data to another zone for garbage collectionpurposes. The controller 408 is configured to DMA read new commands froma submission queue populated by a host device.

In an empty zone 406 just switched to an active zone 406, the data iswritten to the zone 406 starting at the ZSLBA, as the write pointer 410is indicating the logical block associated with the ZSLBA as the firstavailable logical block. The data may be written to one or more eraseblocks or NAND locations that have been allocated for the physicallocation of the zone 406. After the data associated with the writecommand has been written to the zone 406, the write pointer 410 isupdated to point to the next available block in the zone 406 to trackthe next write starting point (i.e., the completion point of the firstwrite). Alternatively, the controller 408 may select an active zone towrite the data to. In an active zone, the data is written to the logicalblock indicated by the write pointer 410 as the next available block.

For example, the controller 408 may receive or pull-in a first writecommand to a third zone 406 c, or a first zone append command. The hostidentifies sequentially which logical block of the zone 406 to write thedata associated with the first command to. The data associated with thefirst command is then written to the first or next available LBA(s) inthe third zone 406 c as indicated by the write pointer 410, and thewrite pointer 410 is advanced or updated to point to the next availableLBA available for a host write (i.e., WP>0). If the controller 408receives or pulls-in a second write command to the third zone 406 c, thedata associated with the second write command is written to the nextavailable LBA(s) in the third zone 406 c identified by the write pointer410. Once the data associated with the second command is written to thethird zone 406 c, the write pointer 410 once again advances or updatesto point to the next available LBA available for a host write. Resettingthe zone 406 c moves the write pointer 410 back to the Z_(c)SLBA (i.e.,WP=0), and the zone 406 c switches to an empty zone.

FIG. 5A is a schematic illustration of a ZNS 500 of a storage device forstoring data, according to one embodiment. FIG. 5B is a flowchartillustrating a method 575 of writing data to the ZNS 500 of FIG. 5A,according to one embodiment. The storage device (not shown) may be thestorage device 106 of FIG. 1 , the storage device 206 of FIG. 2 , or thestorage device 400 of FIG. 4A. The controller of the storage device maybe the controller 108 of FIG. 1 or the controller 408 of FIG. 4A. TheZNS 500 may be the ZNS 402 of FIGS. 4A-4B. The ZNS 500 comprises aplurality of zones. For example, a first Zone 1 502 and a second Zone 2530 are shown. As discussed above, each zone 502, 530 of the ZNS 500 maycomprise any number of erase blocks. For example, each zone 502, 530 isshown to comprise 8 erase blocks, but may comprise additional or fewererase blocks, such as 64 erase blocks from 32 die that each possess 2planes. Additionally, each zone of the plurality of zones may have thesame zone capacity (i.e., the amount of writeable capacity for storingdata). Zones are an interface descriptive entity and may have noimplications on the physical NAND activity. Additionally, therelationship of zones to physical NAND activity is not required.Therefore, the separation of logical host interface activity to physicaldevice activity may be an advantage for the efficiency of a storagedevice.

In the following figures and corresponding description, data is denotedby “Dxx” where “x” represents a write ID of an associated command.Furthermore, pad data or dummy data is denoted by “DUMMYxx” where “x”represents a pad or a dummy write ID. The method 575 of FIG. 5B will bedescribed with reference to the ZNS 500 of FIG. 5A. In FIGS. 5A-7B, theterm “DUMMY” data may refer to any data entered to pad a zone to thezone capacity. Dummy data or pad data may be any set of data that thecontroller recognizes is not user data, XOR or parity data, metadata, orany other usable data not listed. Some options of dummy data or pad dataare sets of 0s, sets of 1s, sentinel values specifically chosen to havea meaning (i.e., to be used for dummy data or pad data), for example,internal drive code for “unwritten data”, randomly written data, or anyof the previously listed through a scrambling or encryption algorithm.The various options for dummy data or pad data may be used as an addeddebugging capability.

At block 572, the storage device, such as a controller of the storagedevice, receives one or more first commands to write data D00 504, D01506, D02 508, D03 510 to the first zone 502 from a host, such as thehost 204 of FIG. 2 . At block 574, the data associated with the one ormore first commands D00 504, D01 506, D02 508, D03 510 is then writtento a first portion 520 of the first zone 502. At block 576, thecontroller determines that a predetermined amount of time has passedsince receiving a command to write data to the first zone 502. At block578, the second portion 522 of the first zone 502 that is currentlyempty is then temporarily filled with a pad or dummy data set DUMMY01512, DUMMY02 514, DUMMY03 516, DUMMY04 518 to fill the first zone 502 toa zone capacity. Filling the first zone 502 with the dummy data DUMMY01512, DUMMY02 514, DUMMY03 516, DUMMY04 518 switches the first zone 502to the closed and active state. The term “DUMMY” data may refer to anydata entered to pad the first zone 502 to the zone capacity, asdiscussed above.

The controller of the storage device may comprise a timer or othermechanism to determine that the predetermined amount of time has passedor expired (e.g., to time or track the amount of time that a zone hasbeen in the open state). The timer may be configured to expire after thepredetermined amount of time to trigger the padding of a zone due to apreviously characterized exposure risk of open EB time to bit erroraccumulation. The relationship of EB open time to previously accumulatedprogrammed bit error accumulation may or may not be a function of openedEB time (i.e., may be the time from erased EB to fully programmed EB).The predetermined amount of time may be based off the type of flashstorage of the first zone 502 (e.g., SLC, MLC, TLC, QLC, or otheriterations of multi-level cells). For example, the predetermined amountof time for QLC may be in the range of, but not limited to, about 15minutes to about three days. In another example, TLC may have apredetermined amount of time of, but not limited to, about one day toabout seven days. Thus, the predetermined amount of time may be betweenabout 15 minutes to about seven days or more. These predetermined timesmay incorporate a threshold of acceptable bit error rate accumulationduring the time the EB is in a partially filled state. The predeterminedtimes may incorporate increased levels of complexity such ascharacterizing different lengths of time for different quantities ofpartially written data in the EB. Such predetermined amounts of timeshould not be taken as limiting, but as generally accepted by theindustry.

If the first zone 502 is not filled after the predetermined amount oftime passes or expires, data reliability may decrease due to the openstate of the first zone 502. Exposure of data in a zone in an open statemay potentially lead to the accumulation of erroneous bits. Theaccumulation of erroneous bits may potentially lead to a loss in data inthe zone. The decreased time a zone is left in the open and active statemay reflect in a greater reliability of the NVM.

At block 580, the storage device receives one or more second commands towrite data D04 524, D05 526, D06 528, D07 532 to the first zone 502 fromthe host device. At block 582, a second zone 530 is then allocated andopened when the one or more second commands are received since the firstzone 502 is at the zone capacity. If the second zone 530 is currentlystoring old or outdated data, the erase blocks in the second zone 530may be erased prior to writing the data associated with the one or moresecond commands D04 524, D05 526, D06 528, D07 532. The data associatedwith the one or more second commands D04 524, D05 526, D06 528, D07 532is then written to a first portion 534 of the second zone 530.

At block 584, the data associated with the one or more first commandsD00 504, D01 506, D02 508, D03 510 is re-written to a second portion 536of the second zone 530. Thus, the second zone 530 is filled to a zonecapacity with the data associated with the one or more first commandsD00 504, D01 506, D02 508, D03 510 and the data associated with the oneor more second commands D04 524, D05 526, D06 528, D07 532.

Upon re-writing the data associated with the one or more first commandsD00 504, D01 506, D02 508, D03 510 to the second portion 536 of thesecond zone 530, the first zone 502 can be erased at block 586. Thefirst Zone 1 502 may then be allocated back into the available resourcepool. The end result is the second Zone 2 530 being filled to the zonecapacity.

FIG. 6A is a schematic illustration of a ZNS 600 of a storage device forstoring data, according to another embodiment. FIG. 6B is a flowchartillustrating a method 675 of writing data to the ZNS 600 of FIG. 6A,according to one embodiment. The storage device (not shown) may be thestorage device 106 of FIG. 1 , the storage device 206 of FIG. 2 , or thestorage device 400 of FIG. 4A. The controller of the storage device maybe the controller 108 of FIG. 1 or the controller 408 of FIG. 4A. TheZNS 600 may be the ZNS 402 of FIGS. 4A-4B. The ZNS 600 comprises aplurality of zones. For example, a first Zone 1 602, a second Zone 2630, and a third Zone 3 650 are shown. As discussed above, each zone602, 630, 650 is shown to comprise 8 erase blocks, but may compriseadditional or fewer erase blocks, such as 64 erase blocks from 32 diethat each possess 2 planes. Additionally, each zone of the plurality ofzones may have the same zone capacity (i.e., the amount of writeablecapacity for storing data). The method 675 of FIG. 6B will be describedwith reference to the ZNS 600 of FIG. 6A.

At block 672, the storage device, such as a controller of the storagedevice, receives one or more first commands to write data D00 604, D01606, D02 608, D03 610 to the first zone 602 from a host, such as thehost 204 of FIG. 2 . The data associated with one or more first commandsD00 604, D01 606, D02 608, D03 610 is then written to a first portion620 of the first zone 602. At block 674, the controller determines thata predetermined amount of time has passed since receiving a command towrite data to the first zone 602. The second portion 622 of the firstzone 602 that is currently empty is then temporarily filled with a pador dummy data set DUMMY01 612, DUMMY02 614, DUMMY03 616, DUMMY04 618 tofill the first zone 602 to a zone capacity. Filling the first zone 602with the dummy data DUMMY01 612, DUMMY02 614, DUMMY03 616, DUMMY04 618switches the first zone 602 to the closed and active state. The term“DUMMY” data may refer to any data entered to pad a zone to the zonecapacity, as discussed above.

The controller of the storage device may comprise a timer or othermechanism to determine that the predetermined amount of time has passedor expired (e.g., to time or track the amount of time that a zone hasbeen in the open state). The timer may be configured to expire after thepredetermined amount of time to trigger the padding of a zone due to apreviously characterized exposure risk of open EB time to bit erroraccumulation. The relationship of EB open time to previously accumulatedprogrammed bit error accumulation may or may not be a function of openedEB time (i.e., the time from erased EB to fully programmed EB). Thepredetermined amount of time may be based off the type of flash storageof the first zone 602 (e.g., SLC, MLC, TLC, QLC, or other iterations ofmulti-level cells), such as between about 15 minutes to about seven daysor more. These predetermined times may incorporate a threshold ofacceptable bit error rate accumulation during the time the EB is in apartially filled state. The predetermined times may incorporateincreased levels of complexity such as characterizing different lengthsof time for different quantities of partially written data in the EB.Such predetermined amounts of time should not be taken as limiting, butas generally accepted by the industry.

If the first zone 602 is not filled after the predetermined amount oftime passes or expires, data reliability may decrease due to the openstate of the first zone 602. Exposure of data in a zone in an open statemay potentially lead to the accumulation of erroneous bits. Theaccumulation of erroneous bits may potentially lead to a loss in data inthe zone. The decreased time a zone is left in the open and active statemay reflect in a greater reliability of the NVM.

At block 676, the storage device receives one or more second commands towrite data D04 624, D05 626, D06 628 to the first zone from the hostdevice. A second zone 630 is then allocated and opened when the one ormore second commands are received since the first zone 602 is at thezone capacity. If the second zone 630 is currently storing old oroutdated data, the erase blocks in the second zone 630 may be erasedprior to writing the data associated with one or more second commandsD04 624, D05 626, D06 628. The data associated with the one or moresecond commands D04 624, D05 626, D06 628 is then written to a firstportion 642 of the second zone 630.

At block 678, the controller determines that a predetermined amount oftime has passed since receiving a command to write data to the first orsecond zones 602, 630. In one embodiment, the predetermined amount oftime at block 674 is the same as the predetermined amount of time atblock 678. In another embodiment, the predetermined amount of time atblock 674 is different than the predetermined amount of time at block678. The second portion 654 of the second zone 630 that is currentlyempty is then temporarily filled with a pad data set DUMMY05 632,DUMMY06 634, DUMMY07 636, DUMMY08 638, DUMMY09 640 to fill the secondzone 630 to a zone capacity. Filling the second zone 630 with the dummydata DUMMY05 632, DUMMY06 634, DUMMY07 636, DUMMY08 638, DUMMY09 640switches the second zone 630 to the closed and active state.

At block 680, the storage device receives one or more third commands towrite data D07 646 to the first zone 602 from the host device. A thirdzone 650 is then allocated and opened when the one or more thirdcommands are received since the first zone 602 and the second zone 630are both filled to their respective zone capacities. If the third zone650 is currently storing old or outdated data, the erase blocks in thethird zone 650 may be erased prior to writing the data associated withone or more third commands D07 646. The data associated with the one ormore third commands D07 646 is then written to a first portion 652 ofthe third zone 650.

At block 682, the data associated with the one or more first commandsD00 604, D01 606, D02 608, D03 610 is optionally re-written to a secondportion 656 of the third zone 650, and the data associated with one ormore second commands D04 624, D05 626, D06 628 is re-written to a thirdportion 658 of the third zone 650. However, the data written to thethird zone 650 may be stored in a non-sequential order (i.e., the dataassociated with the one or more third commands D07 646 is stored firstwhile the data associated with the one or more second commands D04 624,D05 626, D06 628 is stored last). The DRAM, such as the volatile memory112 of FIG. 1 , comprises a logical to physical (L2P) translation tablethat may track the out of order data (e.g., utilizing pointers). Inanother embodiment, the tracking of the data order may be in themetadata written to the physical media at a predetermined location.Thus, the third zone 650 is filled to a zone capacity with the dataassociated with the one or more first commands D00 604, D01 606, D02608, D03 610, the data associated with one or more second commands D04624, D05 626, D06 628, and the data associated with one or more thirdcommands D07 646.

Upon optionally re-writing the data associated with the one or morefirst commands D00 604, D01 606, D02 608, D03 610 to the second portion656 of the third zone 650, the first zone 602 can be erased at block586. Upon re-writing the data associated with one or more secondcommands D04 624, D05 626, D06 628 to the third portion 658 of the thirdzone 650, the second zone 630 can be erased at block 684. The erasedfirst zone 602 and second zone 630 may be allocated back to theavailable resource pool. The end result is the third Zone 3 650 beingfilled to the zone capacity.

FIG. 7A is a schematic illustration of a ZNS 700 of a storage device forstoring data, according to another embodiment. FIG. 7B is a flowchartillustrating a method 775 of writing data to the ZNS 700 of FIG. 7A,according to one embodiment. The storage device (not shown) may be thestorage device 106 of FIG. 1 , the storage device 206 of FIG. 2 , or thestorage device 400 of FIG. 4A. The controller of the storage device maybe the controller 108 of FIG. 1 or the controller 408 of FIG. 4A. TheZNS 700 may be the ZNS 402 of FIGS. 4A-4B. The ZNS 700 comprises aplurality of zones. For example, a first Zone 1 702, a second Zone 2730, and a third Zone 3 740 are shown. As discussed above, each zone702, 730, 740 is shown to comprise 8 erase blocks, but may compriseadditional or fewer erase blocks such as 64 erase blocks from 32 diethat each possess 2 planes. Additionally, each zone of the plurality ofzones may have the same zone capacity (i.e., the amount of writeablecapacity for storing data). The method 775 of FIG. 7B will be describedwith reference to the ZNS 700 of FIG. 7A.

At block 772, the storage device, such as a controller of the storagedevice, receives one or more first commands to write data D00 704, D01706, D02 708, D03 710 to the first zone 702 from a host, such as thehost 204 of FIG. 2 . The data associated with one or more first commandsD00 704, D01 706, D02 708, D03 710 is then written to a first portion720 of the first zone 702. At block 774, the controller determines thata predetermined amount of time has passed since receiving a command towrite data to the first zone 702. The second portion 722 of the firstzone 702 that is currently empty is then temporarily filled with a pador dummy data set DUMMY01 712, DUMMY02 714, DUMMY03 716, DUMMY04 718 tofill the first zone 702 to a zone capacity. Filling the first zone 702with the dummy data DUMMY01 712, DUMMY02 714, DUMMY03 716, DUMMY04 718switches the first zone 702 to the closed and active state. The term“DUMMY” data may refer to any data entered to pad a zone to the zonecapacity, as discussed above.

The controller of the storage device may comprise a timer or othermechanism to determine that the predetermined amount of time has passedor expired (e.g., to time or track the amount of time that a zone hasbeen in the open state). The timer may be configured to expire after thepredetermined amount of time to trigger the padding of a zone due to apreviously characterized exposure risk of open EB time to bit erroraccumulation. The relationship of EB open time to previously accumulatedprogrammed bit error accumulation may or may not be a function of openedEB time (i.e., the time from erased EB to fully programmed EB). Thepredetermined amount of time may be based off the type of flash storageof the first zone 702 (e.g., SLC, MLC, TLC, QLC, or other iterations ofmulti-level cells), such as between about 15 minutes to about sevendays. These predetermined times may incorporate a threshold ofacceptable bit error rate accumulation during the time the EB is in apartially filled state. The predetermined times may incorporateincreased levels of complexity such as characterizing different lengthsof time for different quantities of partially written data in the EB.Such predetermined amounts of time should not be taken as limiting, butas generally accepted by the industry.

If the first zone 702 is not filled after the predetermined amount oftime passes or expires, data reliability may decrease due to the openstate of the first zone 702. Exposure of data in a zone in an open statemay potentially lead to the accumulation of erroneous bits. Theaccumulation of erroneous bits may potentially lead to a loss in data inthe zone. The decreased time a zone is left in the open and active statemay reflect in a greater reliability of the NVM.

At block 776, the storage device receives one or more second commands towrite data D04 724, D05 726, D06 728 to the first zone 702 from thehost. A second zone 730 is then allocated and opened when the one ormore second commands are received since the first zone 702 is filled. Ifthe second zone 730 is currently storing old or outdated data, the eraseblocks in the second zone 730 may be erased prior to writing the dataassociated with the one or more second commands D04 724, D05 726, D06728. The data associated with the one or more second commands D04 724,D05 726, D06 728 is then written to a first portion 734 of the secondzone 730.

At block 778, the data associated with the one or more first commandsD00 704, D01 706, D02 708, D03 710 is optionally re-written to a secondportion 736 of the second zone 730. Upon optionally re-writing the dataassociated with the one or more first commands D00 704, D01 706, D02708, D03 710 to the second portion 736 of the second zone 730, the firstzone 702 can be erased at block 778. The erased first zone 702 may beallocated back to the available resource pool.

At block 780, the controller determines that a predetermined amount oftime has passed since receiving a command to write data to the first orsecond zones 702, 730. In one embodiment, the predetermined amount oftime at block 774 is the same as the predetermined amount of time atblock 780. In another embodiment, the predetermined amount of time atblock 774 is different than the predetermined amount of time at block780. The third portion 738 of the second zone 730 that is currentlyempty is then temporarily filled with a pad or dummy data set DUMMY05732 to fill the second zone 730 to a zone capacity. The end result is asecond Zone 2 730 filled to the zone capacity. Filling the second zone730 with the dummy data DUMMY05 732 switches the second zone 730 to theclosed and active state.

At block 782, the storage device receives one or more third commands towrite data D07 742 to the first zone 702. A third zone 740 is thenallocated and opened when the one or more third commands are receivedsince the first zone 702 has been erased and the second zone 730 isfilled to the zone capacity. If the third zone 740 is currently storingold or outdated data, the erase blocks in the third zone 740 may beerased prior to writing the data associated with one or more thirdcommands D07 742. The data associated with the third command D07 742 isthen written to a first portion 744 of the third zone 740.

At block 784, the data associated with the one or more first commandsD00 704, D01 706, D02 708, D03 710 that has been re-written to thesecond portion 736 of the second zone 730 and the data associated withone or more second commands D04 724, D05 726, D06 728 that has beenwritten to the first portion 734 of the second zone 730 are optionallyre-written to the second portion 746 of the third zone 740. However, thedata written to the third zone 740 may be stored in a non-sequentialorder (i.e., the data associated with the one or more third commands D07742 is stored first while the data associated with the one or moresecond commands D04 724, D05 726, D06 728 is stored last). The DRAM,such as the volatile memory 112 of FIG. 1 , comprises a logical tophysical (L2P) translation table that may track the out of order data(e.g., utilizing pointers). In another embodiment, the tracking of thedata order may be in the metadata written to the physical media at apredetermined location. Thus, the third zone 740 is filled to a zonecapacity with the data associated with the one or more first commandsD00 704, D01 706, D02 708, D03 710, the data associated with one or moresecond commands D04 724, D05 726, D06 728, and the data associated withone or more third commands D07 742.

Upon optionally re-writing the data associated with the one or morefirst commands D00 704, D01 706, D02 708, D03 710 and the dataassociated with one or more second commands D04 724, D05 726, D06 728 tothe second portion 746 of the third zone 740, the second zone 730 can beerased at block 784. The erased second zone 730 may be allocated back tothe available resource pool. The end result is a third Zone 3 740 filledto the zone capacity.

Zones exist in an open state due to having available erase blocks fordata writes. A zone being in the open state for a prolonged amount oftime may potentially lead to a decrease of data reliability due to anaccumulation of erroneous bits. The accumulation of erroneous bits maylead to the loss of data in a zone. The amount of time a zone can safelyremain in the open state depends on the type of memory cell (e.g., SLC,MLC, TLC, QLC, or other iterations of multi-level cells) and may rangefrom minutes to days. Pad or dummy data may be used to close a zone thatis in an open state, thus preventing errors from occurring in the zone.The decreased time a zone remains in the open and active state mayresult in a greater reliability of the NVM.

In one embodiment, a storage device comprises of a media unit, whereinthe capacity of the media unit is divided into a plurality of zones. Themedia unit comprises a plurality of dies and each of the plurality ofdies comprises a plurality of erase blocks. The storage device furthercomprises a controller coupled to the media unit. The controller isconfigured to receive one or more first commands to write data to afirst zone of the plurality of zones, wherein the data associated withthe one or more first commands is written to a first portion of thefirst zone, and wherein a second portion of the first zone remainsavailable to write data to. The controller is also configured todetermine a predetermined amount of time has passed since receiving afirst command to write data to the first zone and write dummy data tothe second portion of the first zone to fill the first zone to a zonecapacity. The controller is further configured to open a second zone andwrite the data associated with the one or more second commands to afirst portion of the second zone upon receiving one or more secondcommands to write data to the first zone. The controller is alsoconfigured to re-write the data associated with the one or more firstcommands written to the first portion of the first zone to a secondportion of the second zone.

A first zone of a media unit is erased after the data associated withthe one or more first commands is re-written to the second portion ofthe second zone. The predetermined amount of time is between about 15minutes to about 3 days. The predetermined amount of time is betweenabout 1 day to about 7 days. Writing the dummy data to the secondportion of the first zone switches the first zone to a closed and activestate. The controller comprises of a timer, and the timer determines thepredetermined amount of time has passed. The data stored in the thirdzone is stored in a non-sequential order.

In another embodiment, a storage device comprises of a media unit,wherein a capacity of the media unit is divided into a plurality ofzones. The media unit comprises a plurality of dies and each of theplurality of dies comprises a plurality of erase blocks. The storagedevice further comprises a controller coupled to the media unit. Thecontroller is configured to receive one or more first commands to writedata to a first zone of the plurality of zones, wherein the dataassociated with the one or more first commands is written to a firstportion of the first zone, and wherein a second portion of the firstzone remains available to write data to. The controller is alsoconfigured to determine a first predetermined amount of time has passedsince receiving a first command to write data to the first zone. Thecontroller is further configured to open a second zone and write thedata associated with the one or more second commands to a first portionof the second zone upon receiving one or more second commands to writedata to the first zone. The controller is also configured to determine asecond predetermined amount of time has passed since receiving a secondcommand to write data to the first zone. The controller is furtherconfigured to open a third zone and write the data associated with theone or more third commands to a first portion of the third zone uponreceiving one or more third commands to write data to the first zone.The controller is also configured to re-write the data associated withthe one or more first commands written to the first portion of the firstzone to a second portion of the third zone, and re-write the dataassociated with the one or more second commands written to the firstportion of the second zone to a third portion of the third zone.

A first zone of a media unit is filled by writing dummy data to thesecond portion of the first zone to fill the first zone to a zonecapacity upon determining the first predetermined amount of time haspassed. A second zone of a media unit is filled by writing dummy data toa second portion of the second zone to fill the second zone to a zonecapacity upon determining the second predetermined amount of time haspassed. A first zone and a second zone of a media unit is erased uponre-writing the data associated with the one or more first commands tothe second portion of the third zone and re-writing the data associatedwith the one or more second commands to the third portion of the thirdzone. The first predetermined amount of time is the same as the secondpredetermined amount of time. The first and second predetermined amountof time is between about 15 minutes to about 7 days. The firstpredetermined amount of time is different than the second predeterminedamount of time.

In another embodiment, a storage device comprises of a media unit,wherein a capacity of the media unit is divided into a plurality ofzones. The media unit comprises a plurality of dies and each of theplurality of dies comprises a plurality of erase blocks. The storagedevice further comprises a controller coupled to the media unit. Thecontroller is configured to write data associated with one or more firstcommands to a first portion of a first zone. A second portion of thefirst zone remains available to write data to. The controller is alsoconfigured to write dummy data to the second portion of the first zoneto fill the first zone to a zone capacity. The controller is furtherconfigured to open a second zone and write the data associated with theone or more second commands to a first portion of the second zone uponreceiving one or more second commands to write data to the first zone.The controller is also configured to re-write the data associated withthe one or more first commands written to the first portion of the firstzone to a second portion of the second zone. The controller is furtherconfigured to write dummy data to a third portion of the second zone tofill the second zone to a zone capacity upon the timer expiring a secondtime. The controller is also configured to open a third zone and writethe data associated with the one or more third commands to a firstportion of the third zone upon receiving one or more third commands towrite data to the first zone. The controller is further configured tore-write the data associated with the one or more first commands writtento the second portion of the second zone to a second portion of thethird zone, and re-write the data associated with the one or more secondcommands written to the first portion of the second zone to a thirdportion of the third zone.

A first zone of a media unit is erased after the data associated withthe one or more first commands is re-written to the second portion ofthe second zone. A second zone of a media unit is erased upon re-writingthe data associated with the one or more first commands to the secondportion of the third zone and re-writing the data associated with theone or more second commands to the third portion of the third zone. Thetimer is set to expire after a predetermined amount of time, and thepredetermined amount of time is between about 15 minutes to about 7days. Writing the dummy data to the second portion of the first zoneswitches the first zone to a closed and active state. Writing the dummydata to the third portion of the second zone switches the second zone tothe closed and active state. Re-writing the data associated with the oneor more first commands to the second portion of the third zone andre-writing the data associated with the one or more second commands tothe third portion of the third zone causes the data written to the thirdzone to be stored out of sequential order.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A storage device, comprising: a memory device,wherein a capacity of the memory device is divided into a plurality ofzones; and a controller coupled to the memory device, the controllerconfigured to: write dummy data to a partially filled first zone of theplurality of zones to fill the first zone to a zone capacity; uponreceiving one or more commands to write data to the first zone, open asecond zone of the plurality of zones and write the data associated withthe one or more commands to a first portion of the second zone; andre-write the data associated with the partially filled first zone to asecond portion of the second zone.
 2. The storage device of claim 1,wherein the first zone is erased after the data associated with thepartially filled first zone is re-written to the second portion of thesecond zone.
 3. The storage device of claim 1, wherein the dummy datacomprises sentinel values.
 4. The storage device of claim 1, wherein thedummy data comprises internal drive code for unwritten data.
 5. Thestorage device of claim 1, wherein writing the dummy data to thepartially filled first zone switches the first zone to a closed andactive state.
 6. The storage device of claim 1, wherein the controllercomprises a timer.
 7. The storage device of claim 1, wherein the datastored in the first zone is stored in a non-sequential order.
 8. Astorage device, comprising: a memory device, wherein a capacity of thememory device is divided into a plurality of zones; and a controllercoupled to the memory device, the controller configured to: determine apredetermined amount of time has passed since receiving a first commandto write data to a first zone of the plurality of zones; upon receivingone or more second commands to write data to the first zone, open asecond zone of the plurality of zones and write the data associated withthe one or more second commands to the second zone; and re-write thedata associated with the first command written to the first zone to asecond portion of the second zone.
 9. The storage device of claim 8,wherein the controller is further configured to: write dummy data to thefirst zone to fill the first zone to a zone capacity upon determiningthe predetermined amount of time has passed.
 10. The storage device ofclaim 8, wherein the predetermined amount of time is a function whetherthe memory device is SLC, MLC, TLC, or QLC.
 11. The storage device ofclaim 8, wherein the controller is further configured to: erase thefirst zone upon re-writing the data associated with the first command tothe second zone.
 12. The storage device of claim 8, wherein thecontroller is configured to recognize dummy data as not being user data,XOR data, parity data, or metadata.
 13. The storage device of claim 8,wherein the predetermined amount of time is between about 15 minutes toabout 7 days.
 14. The storage device of claim 8, wherein each zone ofthe plurality of zones has a same capacity.
 15. A storage device,comprising: memory means, wherein a capacity of the memory means isdivided into a plurality of zones; and a controller coupled to thememory means, the controller configured to: write data associated withone or more first commands to a first portion of a first zone of theplurality of zones, and wherein a second portion of the first zoneremains available to write data to; upon a timer expiring a first time,write dummy data to the second portion of the first zone to fill thefirst zone to a zone capacity; upon receiving one or more secondcommands to write data to the first zone, open a second zone of theplurality of zones and write the data associated with the one or moresecond commands to a first portion of the second zone; re-write the dataassociated with the one or more first commands written to the firstportion of the first zone to a second portion of the second zone; uponthe timer expiring a second time, write dummy data to a third portion ofthe second zone to fill the second zone to a zone capacity; uponreceiving one or more third commands to write data to the first zone,open a third zone of the plurality of zones and write the dataassociated with the one or more third commands to a first portion of thethird zone; re-write the data associated with the one or more firstcommands written to the second portion of the second zone to a secondportion of the third zone; and re-write the data associated with the oneor more second commands written to the first portion of the second zoneto a third portion of the third zone.
 16. The storage device of claim15, wherein the controller is further configured to: erase the firstzone upon re-writing the data associated with the one or more firstcommands to the second portion of the second zone.
 17. The storagedevice of claim 15, wherein the controller is further configured to:erase the second zone upon re-writing the data associated with the oneor more first commands to the second portion of the third zone andre-writing the data associated with the one or more second commands tothe third portion of the third zone.
 18. The storage device of claim 15,wherein the timer is set to expire after a predetermined amount of time,and wherein the predetermined amount of time is between about 15 minutesto about 7 days.
 19. The storage device of claim 15, wherein writing thedummy data to the second portion of the first zone switches the firstzone to a closed and active state, and wherein writing the dummy data tothe third portion of the second zone switches the second zone to theclosed and active state.
 20. The storage device of claim 15, whereinre-writing the data associated with the one or more first commands tothe second portion of the third zone and re-writing the data associatedwith the one or more second commands to the third portion of the thirdzone causes the data written to the third zone to be stored out ofsequential order.